Synthesis and silencing properties of siRNAs possessing lipophilic groups at their 3′-termini

Hybrid lipid oligonucleotide conjugates: synthesis, self-assemblies and biomedical applications

“…18,19 More often, related supports have been prepared by immobilization of prefabricated linkerhydrophobic conjugates. [20][21][22][23][24][25][26][27] 3′-terminal modification can be achieved by another type of solid support linked to uridine either at 2′-O 14 and 3′-O 28 through succinyl linker and conjugated with hydrophobic moiety (via carbamate, amide or ether linkage) to the remaining secondary hydroxyl function. There are several phosphoramidite and H-phosphonate reagents reported in the literature, both non-nucleosidic and nucleosidic ones, used to introduce hydrophobic moiety into the 5'-terminus of oligonucleotide chains.…”

Nucleotides and Nucleic Acids; Oligo- and Polynucleotides

“…The attachment of lipophilic groups (palmitic and oleic acids) to siRNA resulted in a decrease in gene silencing, though cholesterol had little effect compared to the un-modified siRNA. 715 However, poly-L-lysin-PEG conjugates of antisense oligonucleotides showed enhanced cellular uptake without endosomal trapping. 716,717 PEG has also been used to conjugate a peptide to siRNA which formed micelles that exhibited enhanced cell uptake and the siRNA showed enhanced gene silencing.…”

Liver-targeted siRNA delivery by polyethylenimine (PEI)-pullulan carrier

“…Many researchers have attempted to induce various chemical modifications into siRNA or to form complexes with several cationic carriers such as cationic polymers, liposomes, peptides, or proteins. [3][4][5] Among cationic polymers, polyethylenimine (PEI) is the most popular synthetic polymer and has a high cationic charge density. It has been widely used to deliver siRNAs into cell lines or tissues.…”